This application is based on application No. 9-18945 filed in Japan, the content of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an image forming apparatus which sorts and ejects image-bearing sheets to multiple bins, and control method for same.
2. Description of the Related Art
Image forming apparatuses, and particularly widely used copiers, are usually provided with sorters to sort and eject recorded copy sheets in predetermined number of sheets per unit in accordance with multi-purpose use and popular copying apparatus.
When, for example, when making ten copies of a thirty-page document while sorting said copies into ten individual units using the aforesaid copying apparatus provided with a sorter, each document page is copied ten times and each said copy sheet is ejected to a sorting bin until ultimately one complete copy of the entire thirty-page document is in each sorting bin (hereinafter, this process of copying a document in plurality and sorting said copies in a predetermined number of bundle units is referred to as "multi-sort copying").
There is a limit to the number of recording sheets which can be ejected to a single sorter bin due to the holding strength said sorting bin and the spacing of said bin with adjacent sorting bins. When this holding capacity is, for example, 50 sheets and the number of sheets of a single copy bundle exceeds said number, the copy operation must be stopped at the point at which the bin capacity is reached. Conventionally, the number of recording sheets ejected to each sorting bin is counted, and when the bin capacity limit is attained, controls are executed so as to eject the remaining recording sheets to an empty bin.
In conventional sorting controls such as the aforesaid, uses a plurality of bins to eject a copy of a single document bundle and the number of bins required for multi-sort copying may exceed the total number of sorting bins.
That is, when making fifteen copies of an 80-page document using a sorter in which each bin has a 50-sheet holding capacity, two bins are required for a single copy bundle because the number of copy pages of a single bundle (i.e., 80 pages) exceeds the 50-sheet capacity of a single sorting bin, therefore a total of 2.times.15=30 sorting bins are required for the all the multi-sort copies. If the total number of all sorting bins is 20, then the first 50 sheets are ejected to the first through fifteenth sorting bins, and the 51st and subsequent sheets are ejected sheet by sheet in the sixteenth and subsequent empty sorting bins, but after ejecting copies to the 20th sorting bin the copy operation is terminated because there are no more empty sorting bins.
In this instance, an operator must remove the ejected recording sheets from each bin, resets the 51st and subsequent documents in an auto document feeder, and restart the copy operation, thereby producing a severely adverse effect on operational characteristics, and markedly reducing copy operation efficiency.